Process of making sulfuric anhydrid.



PATENTED MAR. 24, 1903'.

W. 0. FERGUSON. PROCESS OF MAKING $ULFURIG ANHYDRID.

APPLICATION FILED JUNE 12, 1902.

K0 MODEL.

.MMINESSQJ. W

UNITED STATES FFICE.

\VILLIAM O. FERGUSON, OF FLUSHING, NEIV YORK, ASSIGNOR TO GENERAL CHEMICAL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEIV YORK.

PROCESS OF MAKING SULFU-RIC ANHYDRID.

SPECIFICATION forming part of Letters Patent No. 723.596; date March 1903- Application filed June 12, 1902. Serial No. 111,244. (No specimens.)

To all whom, it may concern:

Be it known that I, WILLIAM C. FERGUSON, a citizen of the United States, residing at Flushing, county of'Queens, State of New York, have invented certain new and useful Improvements in the Manufacture of 'Sulfuric Anhydrid, of which the following is a specification.

My invention relates to the manufacture [O of sulfuric anhydrid according to the contact process, and has for its object to reliably regulate the temperature of the gaseous mixture, and consequently of the contact-chambers, and to gradually dilute the gaseous- :5 mixture so as to obtain a high efficieucy in the output.

The invention will be fully described here inafter and the features of novelty pointed out in the appended claims.

The accompanying drawing is an elevation of a plan suitable for carrying out my invention.

gases containing sulfurous-acid gas, ($0 5 a connecting-pipe 0 leads to the second contact-chamber B, the outlet of which is at another connecting-pipe 0, leading to a third contact-chamber B The outlet of this last- 0 named chamber is indicated at D. The number of contact-chambers may be increased or diminished, but at least two of them are employed. Each connecting tube or pipe 0 O is provided with a branch E E, respectively, p

contact-chamber B becomes partly converted into sulfuric anhydrid,(SO It will be ob- 5o vious that, owing to this partial conversion, the mixture becomes poor in free oxygen, and

' tact operations.

The drawing shows at A the inlet of the B is the first contact-chamber, from which this may diminish the capability of the remainder of SO of becoming converted into sulfuric anhyd rid. At the same time considerable heat. is generated by the conversion, even if it is only a partial one, and the mixture is carried to a temperature which is beyond that most suitable for the continuation of the contact process. It is therefore desirable that the mixture should be cooled, and it is also desirable that before the continuation of the contact process an additional amount of air or oxygen should be introduced into the mixture. It is preferable that the cooling just mentioned should take place during an interruption of the contact process, or, in other words, between two separate con- By thus proceeding I am enabled tobetter mix the added cool air or oxygen with the partially-converted mixture and to avoid a cooling action upon the preceding contact-chamber, which might be detrimental. For this purpose I carry the partially-converted product away from the catalytic substances and ad mix to it, preferably, while it is on its way from one contact-chamber to the next (and not Within the contactchamber) a suitable amount of air which arrives through the pipes E E and may be regulated by the cocks or valves F F. The air may be fed by a blower G. The mixture entering in to the second contact-chamber is thus cooled to the temperature best suited for the contact reaction and, moreover, contains suflicient oxygen for continuing the conversion of the SO into S0 The operation is repeated in the same manner between the second and third contact-chambers. By adding air to the partially-converted mixture after the latter has been carried away from the contact-chamber I'avoid to a very considerable extent any cooling effect which the said air might have upon the preceding contact-chamber.' Furthermore, it will be observed that theladdition of air takes place in a comparatively narrow pipe, so that the air comes in contact with practically every particle of the partially-converted mixture, and as the latter streams through the pipe at a materially-increased speed (as compared with that with which it moves in the contact-chamber proper) the thorough mixture is further promoted by the state of agitation or rapid motion in which the mixture passes from one chamber to the next. It will be understood that these features of my invention while contributing to produce the results. in the best form of my invention now known to me are not all absolutely essential and that some of them may be omitted Without entirely sacrificing the advantages of my invention.

It will be obvious that my improved process, as above described, is also useful on account of the reduced wear of the contactchambers and the material therein, since the temperature does not rise so high as it would if the entire reaction were completed in a single contact-chamber. The use of a mixture rich in SO has the advantage of reducing the volume ofthe original mixture brought into the first contact-chamber as compared with a poorer mixture containing the same amount of SO -that is, in my process the volume of the original gaseous mixture for the, same output of anhydrid is reduced. This is of twofold advantage. First, there is less danger of the accidental formation of anhydrid before the beginning of the contact process, inasmuch as the supply of free oxygen is smaller, and, second, the purification of the mixture previous to the contact process is facilitated partly because the mixture contains less anhydrid (the presence of which renders the purification more difficult) and partly because of the reduced volume of the mixture. The cost of scrubbing is therefore materially decreased.

It will be understood that for practical reasons I prefer to admit atmospheric air through the pipes E Einstead of pure oxygen; but I desire it to be understood that oxygen might be used, and that the term air as used in the claims is to be interpreted as covering oxygen as an equivalent. The air may be admitted at ordinary temperature, or, if an energetic coolingaction is desired, the air may first be artificially cooled.

It will be understood that by adding air to the partially-converted mixture I produce a new mixture in which the proportion of free oxygen to S0 is higher than it would be if instead of a certain volume of air I added the same volume of the original mixture containing air and S0 In the latter case obviously the new mixture would contain a larger proportion of SO to 0 than the partially-converted mixture, while with my process the proportion of free oxygen is increased, so that the second reaction becomes more efficient and more complete than the first. The air or gas'added to the partially-converted mixture contains alarger proportion of free oxygen than the original mixture entering the first contact-chamber,and owing to the change 1. The process of producing sulfuric anhydrid which consists in bringing a mixture containing sulfurous-acid gas and air into contact with catalytic substances in such proportions as to convert only a portion of the sulfurous-acid gas into sulfuric anhydrid, then carrying the partially converted mixture away from the catalytic substances, and mixing cool air with the said partially-converted product, and thereupon bringing the mixture of such air and the partially-converted product into renewed contact with catalytic substances to continue the conversion into sulfuric anhydrid.

2. The process of manufacturing sulfuric anhydrid, which consists in bringing a mixture containing air and a high proportion of sulfurous-acid gas into contact with catalytic substances in such proportions as to convert only a portion of the sulfurous-acid gas into sulfuric anhydrid, carrying the partially-com verted product, which is relatively poor in oxygen, away from the catalytic substances, adding to the partially-converted product, while it is away from the catalytic substances, a suitable amount of air to cool said product and to supply additional oxygen, and thereupon bringing the mixture of air and partially-converted product in renewed contact with catalytic substances to continue the conversion'of sulfurous-acid gas into sulfuric ane hydrid.

3. The'process of producing sulfuric anhydrid which consists in bringing a mixture containing sulfurous-acid gas and free oxygen into contact with catalytic substances in such proportions as to convert only a portion of the sulfurous-acid gas into sulfuric anhydrid,

then carrying the partially-converted mixture away from the catalytic substances, and adding to the partially-converted product a gaseous medium containing a larger proportion of free oxygen than the original mixture, and thereupon bringing the new mixture formed by said medium and by the partially-converted product, into renewed contact with catalytic substances to continue the conversion into sulfuric anhydrid.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WILLIAM G. FERGUSON.

Witnesses:

J OHN LOTKA, EUGENE EBLE. 

